| 摘要 |
An apparatus comprises a light source (70) including LED's (71) arranged on a substrate (89) which is parallel with a bottom surface (75) of a light pipe (73), each LED emitting light away from the substrate, the light being within a cone of angles and having an excitation wavelength, the light pipe receives the light, through an edge surface. Light within the cone of angles is totally reflected from a top surface (74), the light pipe also includes means to redirect some of the light through the top surface. A light conversion layer (60) overlies the top surface and converts light of the excitation wavelength to light having a different wavelength and a reflector (72) for reflecting light into the light pipe, chosen such that it reflects all light, that is initially reflected from the top or bottom surface of the pipe, at an angle greater than the critical angle ( r e) of excitation wavelength within the pipe. |
